18-CE15D1-1C-EN
21
Confined
spaces are installations with less than 50 cu. ft. of space per
1000 BTU/ hr input from all equipment installed. Confined spaces are
defined in the table and illustration for various furnace sizes. Air for
combustion and ventilation requirements can be supplied from inside
the building.
1.
The following types of installations will
require
use of OUTDOOR
AIR for combustion, due to chemical exposures:
* Commercial buildings
* Buildings with indoor pools
* Furnaces installed in commercial laundry rooms
* Furnaces installed in hobby or craft rooms
* Furnaces installed near chemical storage areas
Exposure to the following substances in the combustion air supply will
also require OUTDOOR AIR for combustion:
* Permanent wave solutions
* Chlorinated waxes and cleaners
* Chlorine based swimming pool chemicals
* Water softening chemicals
* Deicing salts or chemicals
* Carbon Tetrachloride
* Halogen type refrigerants
* Cleaning solvents (such as perchloroethylene)
* Printing inks, paint removers, varnish, etc.
* Hydrochloric acid
* Cements and glues
* Antistatic fabric softeners for clothes dryers
* Masonry acid washing material
Note:
Extended warranties are not available in some instances.
Extended warranty does not cover repairs to equipment
installed in establishments with corrosive atmospheres,
including but not limited to, dry cleaners, beauty shops, and
printing facilities.
Minimum Free Area in Square Inches Each Opening (Furnace Only)
in a Confined Space
Furnace Max
BTUH.Input
Rtg.
Air From
Inside
Air From Outside
Vertical Duct
(a)
Horizontal
Duct (b)
40,000
250
10
20
60,000
375
15
30
80,000
500
20
40
100,000
100
25
50
(a) 1 Square inch per 4000 BTU/hr Vertical Duct.
(b) 1 Square inch per 2000 BTU/hr Horizontal Duct.
FURNACE
CONFINED
LESS THAN 50 CU. FT.
PER 1000 BTU/HR INPUT
ALL EQUIP. INSTALLED
All air from inside the building The confined space shall be provided
with two permanent openings communicating directly with an
additional room(s) of sufficient volume so that the combined volume
of all spaces meets the criteria for an unconfined space. The total
input of all gas utilization equipment installed in the combined space
shall be considered in making this determination. Refer to the
Minimum Free Area in square inches for confined spaces table, for
minimum open areas required.
CONFINED SPACE
AIR FROM INSIDE BUILDING
CONFINED
SPACE
PERMANENT
OPENINGS
